Chlorine dioxide is of considerable industrial importance and has found use as a disinfectant and in the bleaching of wood pulp, fats, oils and flour. Generally, chlorine dioxide is used as a bleaching agent and for removing tastes and odors from water and the like liquids. More recently, it has been used as an anti-pollutant.
For several of the established uses of the chlorine dioxide, it is desirable to produce the gas in situ so that the chlorine dioxide, upon formation, can be directly put to use either in gaseous form or, after absorption, in the form of an aqueous solution. In many instances, the use of chlorine dioxide solution rather than in the gaseous form is preferred. Chlorine dioxide is absorbed in water and forms chlorous acid, from which the gas can be readily expelled by heating. The presence of chlorous acid in an aqueous solution indicates a reaction of chlorine dioxide with water.
Several processes have previously been proposed for producing chlorine dioxide. Attention is thus directed to U. S. Pat. Nos. 3,684,437, 3,695,839, 3,828,097 and 3,754,079, all of which are directed to the production of chlorine dioxide or chlorous acid from which the chlorine dioxide can be expelled.